Researchers at Michigan State University have upgraded their autonomous swimming robo-fish named Grace—short for Gliding Robot ACE—with the ability to passively glide through the water, potentially letting it swim forever on a single charge.

Right now it's designed for research, but once it gets a taste for humans, we could be looking at a terrifying cross between Jaws and a Terminator... Fantastic.

The upgrades that allow Grace to now fly through the water like an underwater plane include a built-in pump that regulates water ballast so it can ascend or descend to calmer parts of a river or lake. And a moving battery back that slides back and forth in sync with the pump, generating subtle motions that actually propel the fish through the water. And while the dangerous implications of such a creation are far too real, for the time being Grace is only designed to collect samples and report back water conditions and pollution levels wherever it swims. [Michigan State University via NewScientist]